[Samba] Share permission problem if user is member in more than 16 groups on AD

Gaiseric Vandal gaiseric.vandal at gmail.com
Wed Jul 14 10:46:30 MDT 2010

Here is the catch  (at least for some people.)

This can break NFS stuff.    On my PDC I made a similar change.     Home 
directories are not on the PDC.  This fixed the problem of people 
getting login failures when logging into windows if they had more than 
16 groups.  But if a user tries to ssh into the PDC, and he is in more 
than 16 groups, his login will fail because the home directory can not 
be mounted.  But if your samba server is not functioning as an nfs 
client then it shouldn't be an issue.

My PDC is samba 3.4.x.  The BDC's are 3.0.x.   Samba 3.0.x domain 
controllers didn't check  if your Windows groups exceeded the system 
group max.    You could login-  you might not have all the access to 
directories you thought you should  since your effective group list was 
still getting truncated.

With Samba 3.4.x, samba checks to see how may groups you are in, and if 
the exceeds the ngroups_max it aborts your login.   I don't know why.  
It isn't like it is fixing a security hole.  It just gets people mad at me.

On 07/14/2010 07:39 AM, Marcis Lielturks wrote:
> Hi!
> Running OpenSolaris snv_134 with Samba 3.0.37. Samba is successfully 
> joined to AD domain. AD user "user1" is member in 17 AD groups 
> including "group1", but he cannot access Samba share which have read 
> permissions for "group1". If user account is modified and "group1" 
> becomes users primary group, then he can access shares. If user is 
> member of only 16 groups, then permissions work as expected regardless 
> of users primary group.
> Operating systems "ngroups_max" is set to 1024. I tested with local 
> user and was able to add user to 1024 local groups.

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